MacBook Pro display only black screen on direct HDMI connection

The Mac does not rely on windows-like side-loaded "Drivers" which are actually packages of resolutions and settings for a specific display. Instead, it goes straight to the immutable source -- it asks the display itself.

To get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

The (detect displays) button appears in the bottom right corner of the pane (possibly in place of the (Night shift) button when you hold the Option key with the displays pane active.

Check if the HDMI port works at all via another computer.

Check if you are using a good HDMI cable.

Check if the projector is simply set on the wrong input setting by reading the projector manual on how to change the input. If the projector operates via remote, make sure all the buttons of the remote actually work.